The inside wall of a foundry furnace is typically lined with a refractory material to prevent damage to furnace parts caused by extreme heat, such as 1,200° C. to 1,600° C., used to melt metal. The liner of a furnace also functions as an insulating layer to prevent heat loss and improve furnace efficiency in maintaining operation temperatures. Installation of a furnace liner generally involves a lining form that can be made of metal or other suitable materials. A metal form is often kept in a furnace after a lining mix is installed and allowed to melt in heat applied to sinter the lining mix. As needed, the residual metal from the form can be washed out by running an additional heat cycle prior to an operation of melting metal, which, however, reduces the total number of heat cycles a furnace can run. In some instances, sintering aids are used in lining mixes to allow sintering to be completed at lower temperatures and removal of metal forms prior to melting metals. However, use of sintering aids renders liners less refractory and significantly shortens service lives of liners. The industry continues to demand improvement in foundry furnaces.
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